土壤动物多样性的地理分布及其生态功能研究进展

土壤动物多样性地理分布及其生态功能研究已成为地学和生态学等领域共同关注的科学前沿。本文在介绍相关研究最新进展的基础上, 讨论已有研究的局限性或不确定性, 展望未来研究的重点方向。近10年来, 代表性土壤动物类群的全球分布研究取得突破性进展; 国内土壤动物研究的尺度和采样区域也有明显拓展, 尤其在蚯蚓和线虫相关研究上取得了系列成果。结果表明, 土壤动物多样性随纬度的变化模式主要有两种, 即在低纬度的热带最高或在中纬度的温带最高; 而土壤动物多度与多样性可能同步变化、无明显关系、截然不同甚至相反; 降水、植物生产力和土壤有机质是土壤动物分布格局的关键驱动力, 但它们的影响力因土壤动物类群不同而异。土壤动物具有改善土壤物理结构、促进养分循环和有机碳稳定、提高作物健康水平等多重功能; 土壤动物的多功能性评估方兴未艾, 但仍面临诸多挑战。简单分析土壤动物随经纬度等的变化规律存在较大局限性, 考虑在基于地质-生态历史及“经纬度-海拔-离海岸距离”等构建的多维时空框架内, 探究土壤动物分布特征及其驱动力。土壤动物分布格局对其潜在的生态功能有关键影响, 但是目前对土壤动物分布格局的预测和模拟仍主要依靠经验模型; 代谢生态学等理论在土壤动物群落研究中的应用值得关注。探究分类多样性的冗余机制, 突出功能多样性, 可以将生物多样性与生态功能更好地联系起来; 同时, 需要在特定条件和时空下, 从整个土壤食物网及其与植物的联系中理解土壤动物多样性与多功能性的联系。建议未来关注两个研究方向: (1)量化人类活动和气候变化给土壤动物多样性和生态功能带来的巨大不确定性; (2)完善土壤动物群落特征预测的理论框架和开展土壤动物群落的精准调控, 综合评价其多功能性, 进而将土壤动物与人类福祉更紧密地联系起来。

A review of recent advances in the study of geographical distribution and ecological functions of soil fauna diversity

Aims: Understanding the distribution and drivers of soil fauna diversity as well as their ecological functions have become areas of cutting-edge research in modern geoscience and ecology. Here, we briefly introduce the latest progress in this field, discuss present research limitations and uncertainties, and offer promising research directions in future studies of soil fauna. Progresses: Many studies have described the global distribution of representative soil fauna taxa diversity and abundance, such as that of earthworms. Research on soil fauna distribution and ecological function in China has also flourished with many large scale, intensive sampling studies in the past 10 years (especially for earthworms and nematodes). Based on a literature review, we observed that there were two main distribution patterns of soil fauna diversity across latitudes. Diversity was found to be highest either at low-latitude tropical zones or at mid-latitude temperate zones; while changes in soil fauna abundance and diversity can be consistent, non-related, totally different, and even opposite. Precipitation, plant productivity and soil organic matter were the critical drivers of soil fauna distribution, but their influences varied with soil faunal taxon. The major ecological functions of soil fauna include improving soil physical structure, facilitating nutrient cycling and organic carbon stabilization, and enhancing plant health. The concept of multifunctionality of soil fauna has been proposed by soil ecologist to fully measure these multi-dimensional ecological functions, but it still faces many challenges. Prospect: The drivers of soil fauna distribution are not simply predicted from the variation pattern of soil faunal community characteristics across latitudes, longitudes or altitudes. Rather, we suggest that drivers of the soil fauna distribution should be explored within a multi-dimensional spatial-temporal framework based on a combination of geological and ecological history as well as “latitude & longitude-altitude-distance to coast”. The distribution pattern of soil fauna may critically influence their potential ecological functions; however, the prediction and simulation of soil fauna distribution mainly relied on data-driven empirical models, and the results were not conclusive. Thus, the application of theories such as metabolic ecology deserves more attention. Research on the relationship between soil fauna diversity and function is in the preliminary stages; focusing on functional diversity and exploring the redundancy mechanism of taxonomic diversity could link soil fauna diversity and function. We propose to understand soil fauna diversity and function under specific condition of space and time, as well as the context of the whole soil food web and its connection with plants. There are two promising directions for further research: (1) illustrating the large uncertainties that human activity and climate change may bring to soil fauna studies; (2) developing precision manipulation approaches of soil fauna community to ultimately link soil fauna multifunctionality with human well-being.